Speaker: David Parkinson
Affiliation: Korea Astronomy and Space Science Institute


The model of cosmological slow-roll inflation predicts a spectrum of density perturbations in the early Universe, which seed the initial gravitational instabilities that generate the distribution of matter observed today. This power spectrum is predicted to have a spectral index close to one and very small running of that index (10^-3). Inflation also predicts a spectrum of primordial gravitational waves. While the density fluctuations have been measured by the cosmic microwave background and large-scale surveys, and the spectral index has been confirmed to be close to unity, the imprint of primordial gravitational waves have not yet been detected in the CMB polarisation. Here I show that if the upper limit on the gravitational wave amplitude is further reduced, but no detection is made, then slow-roll inflation generically predicts a larger running of the density power spectrum. This running is an alternative probe of the early universe, and the inflationary prediction will be detectable by a combination of future all-sky surveys such as DESI, SPHEREx and CHIME, by 2030. 

About Physics Seminars

The weekly Physics Seminar series focuses on a broad range of physics research within SMP, along with frequent presentations from visiting researchers. Seminars are usually scheduled for 1.00pm on Tuesdays.

The talks are typically more specialised than a colloquium but are often attended by staff and PhD students across a broad range of areas. Speakers are thus encouraged to include introductory material in the talks.

All SMP researchers and HDR students are encouraged to speak. Please email Lewis Williamson to register your interest.

The seminars are open so there is no need to register your attendance.


Physics Annexe (06)
407 (via Zoom as well: https://uqz.zoom.us/j/94116861984)